Oligosaccharides derived from dragon fruit modulate gut microbiota, reduce oxidative stress and stimulate toll-pathway related gene expression in freshwater crustacean Daphnia magna

• Published in: Fish & shellfish immunology Vol. 103; pp. 126 - 134
• Main Authors: Sangkuanun, Thanwarat, Wichienchot, Santad, Kato, Yasuhiko, Watanabe, Hajime, Peerakietkhajorn, Saranya
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-08-2020
• Subjects: Animal Feed - analysis; Animals; Arthropod Proteins - genetics; Arthropod Proteins - immunology; Cactaceae - chemistry; Daphnia - immunology; Daphnia - metabolism; Daphnia - microbiology; Daphnia magna; Diet; Dietary Supplements - analysis; Dose-Response Relationship, Drug; Dragon fruit oligosaccharide; Fruit - chemistry; Gastrointestinal Microbiome - drug effects; Gene Expression - drug effects; Microbiota; Oligosaccharides - administration & dosage; Oligosaccharides - chemistry; Oligosaccharides - metabolism; Oxidative stress; Oxidative Stress - drug effects; Random Allocation; Toll pathway; Oxidative stress; Microbiota; Toll pathway; Dragon fruit oligosaccharide; Daphnia magna
• ISSN: 1050-4648; 1095-9947
• DOI: 10.1016/j.fsi.2020.04.046

Dragon fruit oligosaccharide (DFO) is an indigestible prebiotic. In this study, we aimed to investigate the effects of DFO on gut microbiota, oxidative stress and immune-related gene expression in Daphnia magna. The 10-day-old D. magna were treated with 0, 9, and 27 mg l−1 DFO for 85 h. The gut bacterial communities, superoxide dismutase (SOD) activity, lipid peroxidation and the expressions of genes in Toll signaling pathway were observed. The results showed that D. magna treated with 9 and 27 mg l−1 DFO altered gut microbiota composition by increasing Limnohabitans and Lactobacillus, and significantly increased SOD activity and reduced lipid peroxidation. Moreover, the expressions of Toll2, Toll3, Toll5, Toll7 and Pelle genes were significantly increased in D. magna treated with 9 and 27 mg l−1 DFO. Our results suggested that DFO changed the composition of the gut microbiota of D. magna by increasing the beneficial bacteria. DFO also had the ability to stimulate innate immunity in D. magna by increasing SOD activity, reducing lipid peroxidation, and increasing the expression of immune-related genes.
•This is the first evidence of the effect of dragon fruit oligosaccharides on immunity of Daphnia magna.•Dragon fruit oligosaccharides altered gut microbial composition of Daphnia magna.•Dragon fruit oligosaccharides increased SOD activity and reduced lipid peroxidation.•Dragon fruit oligosaccharides upregulated Toll-pathway related gene expression.